The vast majority of telephone calls are made without operator assistance and without identifying or verifying the parties to the telephone call. Typical telephone calls involve the calling party simply dialing a destination telephone number and talking to whomever answers the called telephone. In some instances, the calling party may have to provide identification information to verify that they are authorized to use the telephone system. This verification of the calling party is usually done for billing purposes, such as to provide a prepaid or credit card account number and personal identification number (PIN), or to provide some other telephone system access number.
The called party is rarely required to provide information to complete a telephone call. For a collect telephone call in which the calling party wants to place a call at the called party's expense, the person answering the call is asked whether they will accept the charges. However, the person answering the called telephone is not asked for identification. In the past, collect calls were only possible as an operator-assisted call, but with the introduction of computer-based telephone dialing equipment, it is now possible to place a collect call without using an operator. Currently, when a collect call is made, the phone system must determine if the called number can be billed for the call. If the number can be billed for the call, the collect call will be connected as long as someone at the called number accepts the call charges. However, the person accepting the call may not be the one responsible for paying for the call. Since there is no way for the computer-based telephone dialing equipment to determine who is accepting the charges at the called number, the collect call may be permitted even though the account owner of the called number does not wish to accept the charges.
In traditional person-to-person calls, an operator's assistance was required to place the call to the destination telephone number and to ask if a particular called party was available. However, there is no way for the operator to verify that the answering person is the designated called party.